Patch

ABSTRACT

According to the invention, a patch provided with a support  1 , an adhesive layer  2  laminated on one side of the support, and a release film  4  attached in a releasable manner to the adhesive layer and having a slit  42  running from one edge to the opposite edge, is characterized in that the shape of the slit in the release film is a wave shape such that, by simply bending the support slightly along the slit while the exposed side of the adhesive layer which has been exposed by peeling off part of the release film along the slit is attached to the attachment site, the edge  44  of the slit of the remaining release film can promptly protrude outward from between the attachment site and the adhesive layer.

This application is the National phase of International ApplicationPCT/JP00/02791, filed 27 Apr. 2000, which designated the U.S., and wasfiled in other than the English language.

TECHNICAL FIELD

The present invention relates to a patch for a plaster or poultice, andmore specifically it relates to a patch that can be easily attached topatch-sites.

BACKGROUND ART

Patches such as shown in FIG. 7 have been known in the prior art. Suchpatches comprise a patch body 30 composed of a roughly rectangularsupport 10 made of a nonwoven fabric or the like and an adhesive layer20 laminated over its entirety, and a release film 40 which is attachedto the adhesive layer in a releasable manner. The release film 40 isprovided with a large wave-shaped slit 50 at approximately the center.

When this type of patch is used, because the release film 40 has awave-shaped slit 50, the portion of the release film along the slit 50separates from the adhesive layer 20 when the patch is bent, as shown inFIG. 7. A separated portion 60 (hereunder referred to as the “gripsection”) of the release film 40 is gripped with the fingers and used topeel off half of the release film 40. In order to make the release film40 easier to grip with the fingers, the height H of the wave-shaped slit50 has conventionally been approximately the size of the fingertip, orabout 15 mm±2 mm. The exposed adhesive layer 20 is then attached to thepatch site such as an affected area of the body, and finally theremaining half of the release film is peeled off while attaching theentire adhesive layer 20.

One of the requirements for conventional patches has been a property toprevent their peeling and falling off during use on areas of the bodysuch as joints and their surrounding muscles which experience activemovement that causes considerable stretching of the skin. A modificationhas therefore been devised whereby the support 10 is given flexibilityand elasticity and the patch body 30 is made thinner to increase itsflexibility and elasticity. On the other hand, release films 40 whichare thin but have suitable rigidity have also been used in order tofacilitate handling of more flexible patches and to allow easier releaseby utilizing the difference in softness with the support 10.

With the conventional patches such as shown in FIG. 7, however, when theadhesive layer 20 of the patch is attached to the affected area of theskin S and the remaining release film 40 is peeled off, as shown inFIGS. 8A and B, the grip section 60 sometimes gets caught between theskin S and the adhesive layer 20 and is difficult to grip with thefinger.

In light of this problem of the prior art, it is an object of thepresent invention to provide a novel patch with a function allowingsmooth attachment to patch sites such as affected areas of the skin.

DISCLOSURE OF THE INVENTION

As a result of much diligent research directed toward achieving theaforementioned object, the present inventors have found that the causeof this problem associated with patches having a large wave-shaped slit50 in the release film 40 is as follows. As shown in FIG. 8A, a highheight H of the wave-shaped slit 50 of the release film 40 providessufficient area as the grip section 60 for release, but also increasesthe area of the adhesive section 70 which inhibits release, and sincethe support 10 is thin with high flexibility and elasticity, thecohesion between the inhibiting adhesive section 70 and the skin S isgreater, such that the bend line R of the support 10 shifts toward thevalley Y end instead of the hill X end of the wave-shaped slit, as shownin FIG. 8.

The present inventors have also found that in order to allow smoothattachment of the patch to the affected area of skin S, it is effectiveto appropriately reduce the height H of the wave-shape slit 50 of therelease film 40, thereby shrinking the area of the grip section 60during release.

The patch of the invention is based on this finding, and specifically,it is a patch provided with a support, an adhesive layer laminated onone side of the support, and a release film attached in a releasablemanner to the adhesive layer and having a slit running from one edge tothe opposite edge, the patch being characterized in that the shape ofthe slit in the release film is a wave shape such that, by simplybending the support slightly along the slit while the exposed side ofthe adhesive layer which has been exposed by peeling off part of therelease film along the slit is attached to the attachment site, the edgeof the slit of the remaining release film can promptly protrude outwardwithout getting caught between the attachment site and the adhesivelayer. The term “wave-shaped” as used herein will refer to sinewave-like waveforms as well as sawtooth waves.

Specifically, the wave-shaped slit preferably has a wave height of 4 mmto 8 mm. Here, the “wave height” is the value corresponding to theamplitude where the shape of the slit approximates a complete wave, andit is the height represented as “H” in FIG. 4 and FIG. 8.

By using a release film satisfying the above-mentioned condition, it ispossible to easily grip the remaining portion of the release film withthe fingers when peeling it off, without the grip section of the releasefilm getting caught between the attachment site and the support.

The wave-shaped slit of the release film also preferably has a wavepitch of 6 mm to 12.5 mm. Here, the “wave pitch” is the valuecorresponding to the wavelength where the shape of the slit approximatesa complete wave, and it is the height represented by “P” in FIG. 4.

By using a release film satisfying the above-mentioned condition, thegrip section formed in the release film can be given an area of a sizeappropriate to permit protrusion outward from the attachment site andfacilitate gripping with the fingers.

The patch of the invention may also have two wave-shaped slits in therelease film, with the two slits substantially parallel to each other.

A release film satisfying this condition will allow the release film tobe peeled off between the slits before attachment so that the exposedadhesive layer surface can be used as a paste area for provisionalattachment to the attachment site. Since the patch is affixed to theattachment site, such as an affected area, this function allowsattachment while easily peeling off the edge of the remaining releasefilm, for a smoother series of attachment steps. Such provisionalattachment also allows reattachment so that more precise attachment canbe achieved to the desired site of the affected area.

When two wave-shaped slits are formed in the release film, a spacingbetween the slits of 20 mm to 30 mm is effective for the purpose ofcarrying out the function described above.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a first embodiment of the patch of theinvention.

FIG. 2 is an expanded abbreviated cross-sectional view of the sectionalong line II—II in FIG. 1.

FIG. 3 is a plan view showing the state of the patch of FIG. 1 afterhalf of the release film has been peeled off.

FIG. 4 is an expanded abbreviated plan view of section IV in FIG. 3.

FIG. 5A and FIG. 5B are schematic cross-sectional views of an example ofsteps for attachment of a patch according to the first embodiment of theinvention onto the affected area of skin.

FIG. 6 is a plan view of a second embodiment of the patch of theinvention.

FIG. 7 is a perspective view showing the state of a conventional patchwhen bent.

FIG. 8A is a front view showing the state of a conventional patch afterhalf of the release film has been peeled off. FIG. 8B is a schematiccross-sectional view showing the conventional patch after it has beenattached to an affected area of skin in the state shown in FIG. 8A, andthen bent.

BEST MODE FOR CARRYING OUT THE INVENTION

Preferred embodiments of the invention will now be explained in detailwith reference to the attached drawings. In the drawings, identical orcorresponding members are indicated by like reference numerals.

FIG. 1 is a plan view of a first preferred embodiment of the patch ofthe invention, and FIG. 2 is an expanded abbreviated cross-sectionalview along line II—II of FIG. 1.

As shown in FIG. 1 and FIG. 2, the patch of the invention has aconstruction with a patch body 3 comprising a roughly rectangularsupport 1 and an adhesive layer 2 laminated over approximately theentire surface of the support 1, and a release film 4 attached overapproximately the entire surface of the adhesive layer 2 for releaseduring use.

The structural material of the support 1 is not particularly restricted,but it is preferably a film, woven fabric, knitted fabric, nonwovenfabric or laminate thereof, composed of a synthetic resin such aspolyethylene terephthalate (PET), ethylene-vinyl acetate copolymer(EVA), a block copolymer resin composed mainly of vinyl chloride,polyethylene, polybutadiene, styrene-butadiene or styrene-isoprene,butadiene-styrene-methyl methacrylate copolymer, or nylon, polyurethane,alkoxyalkyl (meth)acrylate copolymer, polyvinyl acetal, polyamide, rayonor the like.

The support 1 is preferably one with suitable flexibility andelasticity. The thickness of the support 1 is preferably 0.01 mm to 5mm. A thickness of the support 1 of less than 0.01 mm tends to result inpoor handling properties and tends to produce wrinkles, while athickness of greater than 5 mm tends to reduce the flexibility and tendsto produce an uncomfortable feeling upon attachment, while also tendingto cause more physical irritation.

The main component of the adhesive layer 2 is a pressure-sensitiveadhesive. The structural material is not particularly restricted but ispreferably one with adhesive strength sufficient to fix a drug onto thesurface of the skin for long periods at ordinary temperature, and forexample, there may be mentioned acrylic-based adhesives, rubber-basedadhesives and silicone-based adhesives. Rubber-based adhesives arepreferred for use among these from the standpoint of their satisfactoryadhesive properties and drug release properties, and particularlypreferred for use are natural rubber, synthetic isoprene rubber,polyisobutylene, polyphenyl ether, polyurethane, polyisoprene,polybutadiene, styrene-butadiene copolymer, styrene-isoprene copolymer,styrene-isoprene-styrene block (SIS) copolymer and the like. When a SIScopolymer is used, SIS bases by Shell Chemical Co., Ltd. (trade names:CALIFLEX Tr-1107, CALIFLEX TR-1111, CALIFLEX TR-1112 and CALIFLEXTR-1117), SIS bases by JSR Co., Ltd. (trade names: JSR5000, JSR5002 andJSR5100) and SIS bases by Zeon Corp. (trade name: QUINTAC 3570C) and thelike are most preferred.

If necessary, an additive such as a tackifier, softening agent, filler,antioxidant, absorption accelerator or the like may be added to theadhesive layer 2. Such additives include, for example, tackifiers suchas alicyclic saturated hydrocarbon resins (trade name: ARKON P-100, etc.by Arakawa Chemical Industries, Ltd.), rosin esters (trade names:KE-311, KE-100, etc. by Arakawa Chemical Industries, Ltd.), hydrogenatedrosin esters (trade names: FORAL 105, FORAL 85, etc. by Hercules Co.,Ltd.), hydrogenated alicyclic hydrocarbons (trade name: ESCOREZ 5300,etc. by Exxon Chemical Co., Ltd.), polyterpene resins, petroleum resinsand phenol resins; softening agents such as a liquid paraffin,polybutene, liquid polyisobutylene and animal and vegetable oils; aswell as fillers, antioxidants and the like. If necessary, an absorptionaccelerator may be added to the pressure-sensitive adhesive for improvedskin penetration of the drug, and as examples of such absorptionaccelerators there may be mentioned isopropyl myristate, diethylsebacate, sorbitan monolaurate, sodium oleyl phosphate, sodium laurylsulfate, octylphenyl ether, lauryl ether, lauroyl diethanolamide,lauroyl sarcosine, oleyl sarcosine sugar ester, lecithin, glycyrrhizin,urea, salicylic acid, calcium thioglycolate, lactic acid, lactic acidesters, olive oil, squalene, lanolin, liquid paraffin and glycerin. Inaddition, pigments, aromatics, ultraviolet absorbers, surfactants, pHadjustors and the like may also be added to the pressure-sensitiveadhesive as appropriate depending on the purpose of the patch.

When a drug is to be held in a patch according to this embodiment, itmay be simply combined with the pressure-sensitive adhesive. As examplesof such drugs there may be mentioned general anesthetics, hypnotics,analgesics, antipyretic/antiphlogistic analgesics, steroid hormones,analeptic/psychostimulants, psychoneurotic agents, local anesthetics,myorelaxants, autonomic agents, anti-allergic agents, anti-histamines,cardiac stimulants, antiarrhythmic agents, diuretics, antihypertensiveagents, vasoconstrictors, vasodilators, calcium antagonists,antimicrobial agents, agents for parasitic skin conditions, skinsofteners, antibiotics, antidotes, antitussive agents, antipruriticagents, soporifics, psychoactive agents, antiasthmatic agents, hormonesecretion promoters, antiulcer agents, anticancer agents, vitamins, andthe like.

The thickness (coating thickness) of the adhesive layer is preferably 10μm to 400 μm. If the thickness of the adhesive layer 2 is greater than400 μm, the drug in the pressure-sensitive adhesive tends to have poorrelease properties, and if it is less than 10 μm the adhesion onto skinis reduced, tending to result in peeling.

The patch body 3 comprising the support 1 and the adhesive layer 2 ispreferably cut with rounded corners. Once part of the patch turns up andpeels off, the horny skin layer and dust adhere to that section, makingreattachment difficult. Particularly in cases where the patch has arectangular shape, the corners tend to get caught on clothing, etc., andare the first to turn up and peel off. The patch therefore preferablyhas rounded corners that are less prone to being caught on clothing andthe like, thereby further preventing occurrence of peeling. When thecorners of the patch body 3 are rounded, the roundness preferably has acurvature radius of 5 mm or greater. A radius of less than 5 mm tends toinsufficiently reduce peeling.

As shown in FIG. 1, the release film 4 has a wave-shaped slit 42 at theapproximate center, extending from one edge toward the opposite edge.The height of the slit 42 (height R in FIG. 4) is preferably 4 mm to 8mm, and more preferably 6 mm to 7 mm. The wave pitch of the slit 42(length P in FIG. 4) is 6 mm to 12.5 mm. The reason for this wave heightand wave pitch of the slit 42 is to improve the handleability, as willexplained below.

The release film 4 is released during use, being attached to the entiresurface of the adhesive layer 2 in a releasable manner, and when it isattached to the entire surface of the adhesive layer 2 in a releasablemanner prior to using the patch body 3, an effect is provided ofpreventing wrinkles in the highly flexible and elastic patch body 3 andpreventing escape of the drug component or moisture in the adhesivelayer 2. There are no particular restrictions on the structural materialof the release film 4, and it may be appropriately selected from amongresin films of polyethylene terephthalate, etc., paper and the likehaving a thickness of about 50 μm after release treatment. The releasefilm 4 preferably has appropriate rigidity. The reason for this, as willbe explained below, is for improved handleability of the release film 4for the release procedure, and more satisfactory attachment.

Attachment of a patch having such a construction onto the skin S of anaffected area as the attachment site will now be explained withreference to FIGS. 3 to 5.

First, when the patch is slightly bent along the slit 42 of the releasefilm 4, the edge of the release film 4 along the slit 42 separates fromthe adhesive layer 2 because of the wave shape of the slit 42 of therelease film 4, similar to the case of the conventional patch shown inFIG. 7. Next, a portion of the separated edge, i.e. the grip section 44of the release film 4 shown in FIG. 4, is gripped with the fingers, andone half of the release film 4 split by the slit 42 is peeled off, thusexposing the surface of the adhesive layer 2 to produce the state shownin FIG. 3. The exposed surface of the adhesive layer 2 is then attachedto the attachment site on the affected area of the skin S.

Next, as shown in FIG. 5, the other edge of the release film of thepatch which has not yet been peeled off is gripped with the fingers, andthe patch is bent slightly toward the opposite edge whereby the releasefilm 4 is pulled away, so that the edge along the slit 42 of theremaining release film separates from the adhesive layer 2 whilepromptly protruding out from between the attachment site, i.e. theaffected area of the skin S shown in FIG. 5, and the adhesive layer 2.

The grip section 44 of the slit 42, which is part of the edge along theslit 42 of the remaining release film 4, is gripped with the fingers.

Finally, the protruding edge of the slit 42 of the remaining releasefilm 4 is slid along the surface of the affected area of the skin S, andthe grip section 44 of the slit 42 which has been gripped with thefingers is pulled, whereby it is gradually peeled away, to allow theremaining section of the patch to be satisfactorily attached to theaffected area of the skin S without wrinkles.

The efficacy of the patch of this embodiment which allows such a smoothattachment procedure will now be explained in detail in comparison witha conventional patch.

When, after peeling off one half of the release film 4 in this mannerand attaching the exposed surface of the adhesive layer 2 to theaffected area of the skin S, the entire adhesive layer is attached whilepeeling off the remaining half of the release film, since the height Hof the wave-shaped slit 50 according to the prior art has been about thesize of the fingertip, or a height of about 15 mm±2 mm as shown in FIG.8B, the grip section of the release film 40 is easy to grip with thefinger; however, when the adhesive layer 20 of the patch is attached tothe affected area of the skin S and the remaining release film is peeledoff, the grip section 60 often becomes caught between the skin S and theadhesive layer 20, making it difficult to grip with the fingers.

This occurs because, as shown in FIG. 8A, a high height H of thewave-shaped slit 50 of the release film 40 gives sufficient area for thegrip section 60 for release but also increases the area of therelease-inhibiting adhesive section 70, and as shown in FIG. 8B, sincethe support 10 is thin with high flexibility and elasticity, adhesionbetween the inhibiting adhesive section 70 and the section S increases,such that the bend line R of the support 10 shifts toward the valley Yend instead of the hill X end of the wave-shaped slit.

In contrast, the patch of this embodiment has a wave height H of 4 mm to8 mm for the wave-shaped slit 42 provided on a release film 4 havingsuitable rigidity, which is lower than that of the prior art, while thewave pitch P of the wave-shaped slit 42 is 6 mm to 12.5 mm, andtherefore the area of the grip section 44 shown in FIG. 4 isappropriately small so as to maintain easy gripping while alsoappropriately reducing the area of the adhesive section 22 whichinhibits release of the release film. Even when the support 1 is thinand has high flexibility and elasticity, adhesion between therelease-inhibiting adhesive section 22 and the skin S is reduced, thusallowing the bend line R of the support 1 to shift toward the hill X endinstead of the valley Y end of the wavle-shaped slit.

As a result, as shown in FIGS. 5A and 5B, the patch of this embodimentallows the release film 4 to easily protrude outward to be gripped bythe fingers without getting caught between the skin S and the adhesivelayer 2 during release of the release film, thus preventing the problemillustrated in FIG. 8B, and therefore allows smoother attachment of thepatch to affected areas of skin S compared to the prior art.

If the wave height H of the wave-shaped slit 42 provided in the releasefilm 4 is less than 4 mm it becomes difficult to grip with the fingers,while if it is greater than 8 mm it becomes gradually more difficult forthe grip section 44 of the release film to flip out from between theskin S and the adhesive layer 2. If the wave pitch P of the wave-shapedslit 42 is less than 6 mm, the grip section 44 of the release film isdifficult to grip even when it protrudes out, while if it is greaterthan 12.5 mm it becomes gradually more difficult for the grip section 44of the release film to flip out from between the skin S and the adhesivelayer 2.

It is effective for the release film 4 on the patch of this embodimentto have appropriate rigidity, in order to give an effect in which therelease film easily protrudes out from between the skin S and theadhesive layer 2, as shown in FIG. 5A and in order to allow unwrinkled,satisfactory attachment when attaching the entire adhesive layer to theskin S while peeling off the other half of the release film from thestate shown in FIG. 5B, since the patch is gradually attached to theskin S while maintaining sufficient firmness due to the release film.

In addition, the ease of the release procedure of the patch of thisembodiment is effective from the standpoint of allowing the adhesivestrength of the contact surface between the release film 4 and theadhesive layer 2 to be set to within a wider range than according to theprior art, and of providing the following advantages for storage priorto use or for the production process, which have not existed in theprior art.

Firstly, since release of the release film 4 from the adhesive layer 2has been difficult according to the prior art, it has been necessary toreduce the adhesive strength to some degree, and this has led to theproblem of peeling of the release film 4 before use which exposes theadhesive layer 2 and permits escape of the drug component or moisture inthe adhesive layer 2, or the problem of peeling from the skin afterattachment; however, the patch of the present invention can adequatelyprevent such problems since the adhesive strength can be set within awider range than according to the prior art.

Secondly, when the adhesive strength is increased between the releasefilm 4 and the adhesive surface of the adhesive layer 2 according to theprior art, it has been necessary to subject the release film 4 tospecial working such as embossing, but with the easier release procedurea smooth film is sufficient. This allows simplification of theproduction process, while also offering improvement in productivity andlower cost compared to the prior art.

The patch of the invention may alternatively have two wave-shaped slits42 in the release film 4 such as shown in FIG. 6.

When the release film 4 is provided with two wave-shaped slits 42, thepositional relationship between the slits 42 is preferably substantiallyparallel. Here, “substantially parallel” means that where the twowave-shaped slits approximate complete waves, the center line of eachwave which bisects the wave amplitude is parallel to the short side ofthe rough rectangular shape of the release film. When two slits areprovided, the slits 42 are preferably formed at a spacing of 20 mm to 30mm.

Attachment of a patch to an affected area of skin S will now beexplained with reference to FIG. 6, for a case where two wave-shapedslits 42 are formed in the release film 4.

First, when the patch is slightly bent along one of the two wave-shapedslits 42 of the release film 4, the edge of the release film 4 along theslit 42 separates from the adhesive layer 2 because of the wave shape ofthe slit 42 of the release film 4. Next, a portion of the edge of therelease film that has separated from the adhesive layer 2, i.e. the gripsection 44 shown in FIG. 4, is gripped with the fingers, and the releasefilm 46 between the two slits 42 which is roughly at the center of therelease film 4 is peeled off first. The surface of the adhesive layer 2that has been exposed after peeling off the release film 46 between thetwo slits 42 is attached to the desired area of the affected area S forprovisional affixment of the patch.

Next, as in FIG. 5, the edges of the non-released sections 48 of therelease film which are at both ends of the paste area of the patchprovisionally affixed to the affected area S are gripped with thefingers, and the patch is bent slightly so that the release film 4 ispulled away, whereby each edge along the slit 42 of the remainingrelease film separates from the adhesive layer 2 while promptlyprotruding out from between the attachment site, i.e. the affected areaof the skin S shown in FIG. 5, and the adhesive layer 2.

The grip section 44 of each slit 42, which is part of the edge along theslit 42 of the remaining release film 4, is gripped with the fingers.

Finally, the protruding edge of the slit 42 of the remaining releasefilm 4 is slid along the surface of the affected area of the skin S, andthe grip section 44 of the slit 42 which has been gripped with thefingers is pulled, so that the end sections 48 of the release film 4 aregradually peeled away either one at a time or both simultaneously, toallow the remaining section of the patch to be satisfactorily attachedto the affected area of the skin S without wrinkles.

Providing two wave-shaped slits 42 in the release film 4 is effectivefrom the standpoint of allowing the release film 46 between the slits 42to be peeled off before attachment so that the exposed adhesive surface2 can be used as a paste area for provisional attachment onto theaffected area. This function permits reattachment so that more preciseattachment to the desired site of the affected area can be achieved.Furthermore, since the patch is adequately affixed to the affected areaS before the entire patch is attached, it is possible to subsequentlyattach the remaining end sections 48 of the release film 4 easily whilepeeling them off, so that the attachment procedure can be carried outmore smoothly.

Sufficiently ensuring a spacing of 20 mm to 30 mm between thewave-shaped slits 42 when two wave-shaped slits 42 are provided in therelease film 4 is effective as it allows formation of a suitably sizedpaste area. Sufficiently ensuring such a spacing between the wave-shapedslits 42 will allow the patch to be firmly affixed to the affected areabeforehand, so that the patch can maintain adequate firmness establishedby the paste area to avoid slipping or peeling off of the patch from theaffected area when the remaining end sections 48 of the release film arepulled off, such that satisfactory attachment with no wrinkles can beeasily accomplished even with one hand.

Here, it should be noted that the efficacy of providing two wave-shapedslits 42 in the release film 4 only functions when the heights of thewave-shaped slits 42 in the release film 4 are smaller than the priorart, within a suitable range. Even if two wave-shaped slits 42 of a sizeaccording to the prior art are provided and the release film 46 betweenthe slits is peeled off to use the exposed adhesive layer surface as apaste area for provisional attachment to the affected area of the skinS, the problem of difficulty when peeling the end sections 48 of therelease film will still occur. Also, since the adhesive strength betweenthe release film 4 and the adhesive layer 2 cannot be increased asmentioned above, the effect of the present invention whereby a pastearea is used for provisional attachment of the patch to the affectedarea of the skin S, is inadequate.

The aforementioned explanation dealt with a preferred embodiment of thepresent invention, but this embodiment is of course not intended torestrict the invention. For example, The wave shape of the slit of therelease film is not limited to the one used for this embodiment.Specifically, it may be a sawtooth wave or rectangular wave. Likewise,the position of the slit of the release film is not limited to the oneused for this embodiment.

In the embodiment described above, the patch was described as a plasteror the like comprising a dry adhesive containing a drug, but the patchof the invention may also contain a moist ointment such as a poultice asthe adhesive.

There are no particular restrictions on such moist ointments, but theypreferably have adhesive strength capable of fixing drugs onto thesurface of the skin for long periods at ordinary temperature and mayalso contain water, thickeners, humectants, fillers or, depending on theneed, crosslinking agents, polymerization agents, dissolving aids,absorption accelerators, drug effect adjuvants, stabilizers,antioxidants, emulsifiers, drug agents and the like.

Preferred thickeners to be used in moist ointments are those that canstably maintain a moisture content of 30-80% and have water retentionproperties. Specific examples that may be suitably used arewater-soluble polymers that include natural polymers which arevegetable-based such as guar gum, locust bean gum, carrageenan, alginicacid, sodium alginate, agar, gum Arabic, tracaganth gum, karaya gum,pectin, starch, etc., microorganic-based such as xanthan gum, acaciagum, etc. and animal-based such as gelatin, collagen, etc.;semi-synthetic polymers which are cellulose-based such as methylcellulose, ethyl cellulose, hydroxyethyl cellulose,carboxymethylcellulose sodium, etc. and starch-based such as solublestarch, carboxymethyl starch, dialdehyde starch, etc.; and syntheticpolymers which are vinyl-based such as polyvinyl alcohol,polyvinylpyrrolidone, polyvinyl methacrylate, etc., acrylic-based suchas polyacrylic acid, polysodium acrylate, etc.; as well as polyethyleneoxide, methylvinyl ether/maleic anhydride copolymer and the like.

Polyacrylic acid is particularly preferred as a thickener from thestandpoint of high gel strength and excellent water retention, andpolysodium acrylate with an average polymerization degree of 20,000 to70,000 is more preferred. With an average polymerization degree of lessthan 20,000 the thickening effect becomes weaker tending to result ininsufficient gel strength, and with an average polymerization degree ofgreater than 70,000 the thickening effect becomes too strong, tending toreduce the workability.

As humectants to be used in moist ointments there may be mentionedpolyhydric alcohols such as glycerin, propylene glycol and sorbitol, andas fillers there may be mentioned kaolin, talc, titanium, bentonite,aluminum silicate, titanium oxide, zinc oxide, aluminum metasilicate,calcium sulfate, calcium phosphate and the like.

In addition, propylene carbonate, crotamiton, 1-menthol, peppermint oil,limonene, diisopropyl adipate and the like may be added as dissolvingaids or absorption accelerators and methyl salicylate, glycolsalicylate, 1-menthol, thymol, peppermint oil, limonene, nonylicvanillylamide, pepper extract and the like may be added as drug effectadjuvants to a moist ointment for the invention. If necessary,stabilizers, antioxidants, emulsifiers and the like may also be added toa moist ointment for the invention.

Depending on the need, a crosslinking agent or polymerization agent maybe added to the moist ointment to reinforce the moist ointment(adhesive) and provide water retention. Such crosslinking agents andpolymerization agents may be appropriately selected depending on thetype of thickener, etc.

For example, when polyacrylic acid or a polyacrylic acid salt is used asa thickener, there may be suitably used a compound with at least twoepoxy groups in the molecule, an inorganic acid salt such as ahydrochloride, sulfate, phosphate or carbonate or an organic acid saltsuch as a citrate, tartrate, gluconate or stearate of Ca, Mg or Al, apolyvalent metal compound, for example, an oxide such as zinc oxide orsilicic anhydride, or a hydroxide such as aluminum hydroxide ormagnesium hydroxide. When polyvinyl alcohol is used as a thickener,there may be suitably used adipic acid, thioglycolic acid, epoxycompounds (epichlorhydrin), aldehydes, N-methylol compounds andcomplexes containing Al, Ti, Zr, Sn, V, Cu, B, Cr and the like. Whenpolyvinylpyrrolidone is used as a thickener, there may be suitably usedmethylvinyl ester/maleic anhydride copolymer, polyacid compounds oralkali metal salts (of polyacrylic acid, tannic acid or theirderivatives). When polyethylene oxide is used as a thickener, there maybe suitably used peroxide, polysulfoneazide or the like. Whenmethylvinyl ether/maleic anhydride copolymer is used as a thickener,there may be suitably used polyfunctional hydroxy compounds, polyamine,iodine, gelatin, polyvinylpyrrolidone, iron, silver, lead salts and thelike. When gelatin is used as a thickener, there may be suitably usedaldehydes such as formaldehyde, glutaraldehyde and dialdehyde starch,diepoxides such as glyoxal and butadiene oxide, diketones such asdivinyl ketone, diisocyanates, and the like.

When a drug agent is to be held in a moist ointment layer, the drugagent may be simply be combined with the moist ointment layer. Asexamples of such drug agents there may be mentioned general anesthetics,hypnotics, analgesics, antipyretic/antiphlogistic analgesics, steroidhormones, analeptic/psychostimulants, psychoneurotic agents, localanesthetics, myorelaxants, autonomic agents, anti-allergic agents,anti-histamines, cardiac stimulants, antiarrhythmic agents, diuretics,antihypertensive agents, vasoconstrictors, vasodilators, calciumantagonists, antimicrobial agents, agents for parasitic skin conditions,skin softeners, antibiotics, antidotes, antitussive agents, antipruriticagents, soporifics, psychoactive agents, antiasthmatic agents, hormonesecretion promoters, antiulcer agents, anticancer agents, vitamins andagents with a whitening effect such as skin beautifying components.

The thickness (coating thickness) of the moist ointment layer laminatedon the support is preferably 0.1 mm to 3 mm. If the thickness of themoist ointment layer is greater than 3 mm, the drug in the moistointment tends to have poor release properties, and if it is less than0.1 mm the adhesion onto skin is reduced, tending to result in peeling.

The thickness including the support and the moist ointment layer(poultice thickness) is preferably 0.5 mm to 5 mm. If the poulticethickness is greater than 5 mm, the poultice tends to get caught onclothing, etc. and peel off when attached, while if it is less than. 0.5mm the poultice tends to lose its support property, leading tomisattachment.

The patch of the invention will now be explained in greater detail byway of examples and comparative examples which are not, however,intended to restrict the invention in any way.

EXAMPLE 1

A patch such as shown in FIG. 1 and FIG. 2 was fabricated in a mannerequivalent to the patch (7 cm×10 cm) sold by Hisamitsu PharmaceuticalCo., Inc. under the trade name “LA SALONPAS” but with the followingconditions. Number of wave-shaped slits in release film: 1, wave heightof wave-shaped slit: 4 mm, wave pitch of wave-shaped slit: 12.5 mm.

EXAMPLE 2

A patch equivalent to the one used in Example 1 was fabricated with thefollowing conditions different from Example 1. Wave height ofwave-shaped slit of release film: 5 mm, wave pitch of wave-shaped slit:6 mm.

EXAMPLE 3

A patch equivalent to the one used in Example 1 was fabricated with thefollowing conditions different from Example 1. Wave height ofwave-shaped slit of release film: 6 mm, wave pitch of wave-shaped slit:8.5 mm.

COMPARATIVE EXAMPLE 1

A patch equivalent to the one used in Example 1 was fabricated with thefollowing conditions different from Example 1. Wave height ofwave-shaped slit of release film: 14 mm, wave pitch of wave-shaped slit:36 mm. This sample corresponds to a prior art product.

COMPARATIVE EXAMPLE 2

A patch equivalent to the one used in Example 1 was fabricated with thefollowing conditions different from Example 1. Wave height ofwave-shaped slit of release film: 5 mm, wave pitch of wave-shaped slit:20 mm.

COMPARATIVE EXAMPLE 3

A patch equivalent to the one used in Example 1 was fabricated with thefollowing conditions different from Example 1. Wave height ofwave-shaped slit of release film: 12 mm, wave pitch of wave-shaped slit:10 mm.

[Performance Comparison Test]

The patches of Examples 1-3 and Comparative Examples 1-3 above weresubjected to a performance comparison test to evaluate the releasingease of the release films in the following manner.

Five of each of the patches of the examples were prepared. One half ofeach release film was peeled off, and the patch was smoothly attached toan acrylic board. Next, the other end of the unreleased section of thepatch was gripped with the fingers as shown in FIG. 5, the patch wasbent thus turning over the release film, and comparison was made basedon the average value for the bend angle as measured at the point wherethe grip section of the slit separated from the adhesive layer.

By comparing the size of the bend angle, it is possible to compare theease with which the grip section of the slit of the release filmprotrudes out. A smaller bend angle indicates that the grip section ofthe slit of the release film more promptly and easily protrudes outwithout getting caught between the patch body and the acrylic board,which represents the affected area of skin.

Also, by comparing the size of the bend angle at the point where thegrip section of the slit of the release film separates from the adhesivelayer, it is possible to compare the ease with which the grip section ofthe slit of the release film can be gripped.

In other words, the smoothness of the attachment procedure can becompared by comparing the “protruding ease” and “gripping ease” of thegrip section of the slit of the release film.

The test results for these samples are shown in Table 1 based on theevaluation criteria for the “protruding ease” and “gripping ease” of thegrip section of the slit of the release film.

The evaluation criteria for the “protruding ease” of the grip section ofthe slit of the release film was as follows. 3: Very smooth protrusionof grip section; 2: Smooth protrusion of grip section; 1: Difficultprotrusion of grip section.

The evaluation criteria for the “gripping ease” of the grip section ofthe slit of the release film were as follows. 3: Protruded grip sectionsufficiently large matching size of fingertips and easy to grip with thefingers; 2: Protruded grip section sufficiently large and easy to gripwith fingers; 1: Protruded grip section small and difficult to grip withfingers.

TABLE 1 Wave Wave height pitch of Number of wave- wave- of wave- shapedshaped Pro- Grip- shaped slits slits Bend truding ping slits (/mm) (/mm)angle ease ease Example 1 1 4.0 12.5 85° 2 2 Example 2 1 5.0 6.0 85° 3 2Example 3 1 6.0 8.5 85° 2 3 Comp. Ex. 1 1 14.0 36.0 150°  1 1 Comp. Ex.2 1 5.0 20.0 110°  1 1 Comp. Ex. 3 1 12.0 10.0 120°  1 1

The results in Table 1 clearly show that when one half of the releasefilm was peeled from the wave-shaped slit and the exposed surface of theadhesive layer was attached to the affected area of the skin, and thepatch was then completely attached to the affected area of skin whilepeeling off the remaining release film, as shown in FIG. 5, the gripsections of the wave-shaped slits of Examples 1-3 of the inventionprotruded out with a bend angle of about ½ compared to ComparativeExamples 1-3.

In the case of Comparative Examples 1-3, however, the bend line of thepatch was toward the valley end instead of the hill end of thewave-shaped slit, as shown in FIG. 8, with the same bend angle asExample 1, and the grip section of the wave-shaped slit got caughtbetween the adhesive layer and the acrylic board and could not protrudeout. When the bend angle was further increased while pulling the end ofthe unattached section of the gripped patch in a direction to peel offthe attached section, that is, in the direction of the other edgeopposite the edge of the gripped patch, the bend line of the patchshifted from the valley end to the hill end of the wave-shaped slit, sothat part of the grip section of the wave-shaped slit of the releasefilm protruded out.

As regards the gripping ease of the grip section of the wave-shaped slitof the release film which protruded upon bending, Examples 1-3 were easyto grip with the fingertips, while Comparative Example 1 was difficultto grip with the fingertips since the size of the protruding gripsection was small.

Examples 1-3 were examined in detail to determine the order of theprotruding ease of the grip section of the wave-shaped slit duringbending of the patch and the gripping ease of the grip section. Theresults indicated that the protruding ease of the grip section of thewave-shaped slit was satisfactory in Example 1, and more satisfactory inExamples 2 and 3. Also, the gripping ease of the grip section of thewave-shaped slit was satisfactory in Examples 1 and 2, and moresatisfactory in Example 3. In other words, of Examples 1-3, the patch ofExample 3 allowed the smoothest attachment procedure.

These results confirmed that protrusion of the grip section of the slitis hampered when the wave height of the wave-shaped slit is too high at14 mm or about the size of the fingertip as in Comparative Examples 1-3,while protrusion of the grip section of the slit is only slightlyhampered but difficult to grip when it is less than 4 mm. It was alsoconfirmed that protrusion of the grip section of the slit is hamperedwhen the wave pitch of the wave-shaped slit is greater than 12.5 mm.These numerical ranges vary depending on the use environment, thematerials, etc., and may be appropriately changed within a range thatdoes not fall outside of the scope of the invention.

INDUSTRIAL APPLICABILITY

As explained above, the present invention provides a novel patch with afunction allowing smooth attachment to affected areas of the skin.

More specifically, it provides a novel patch wherein an appropriaterange is set for the height of the wave-shaped slit of the release filmto be lower than according to the prior art, in order to give thefollowing advantages.

Firstly, the release procedure for the release film is easier than bythe prior art.

Secondly, because the release procedure is easier, the adhesive strengthbetween the release film and the adhesive layer can be increased.Consequently, the release film is a smooth film which requires nospecial working such as embossing. This aspect allows simplification ofthe production process, while also offering improvement in productivityand lower cost compared to the prior art. In addition, the easierrelease procedure also prevents release of the release film before useso that escape of the drug component or moisture in the adhesive layercan be prevented.

Thirdly, providing two wave-shaped slits in the release film permitspart of the release film to be used as a paste area, so that thissection can be used for provisional attachment of the patch to thedesired area of the attachment site. By increasing the reliability ofthis procedure step it is possible to further increase the smoothness ofthe attachment procedure.

Fourthly, a wide variety of materials from existing structural materialsto new structural materials can be used as the support and adhesive inthe patch of the invention, in order to ensure the same flexibility,elasticity and adhesion with skin as the prior art.

1. A patch provided with a support, an adhesive layer laminated on oneside of said support, and a release film attached in a releasable mannerto said adhesive layer and having a slit running from one edge to theopposite edge, the patch being characterized in that the shape of theslit in said release film is a wave shape such that, by simply bendingsaid support slightly along said slit while the exposed side of saidadhesive layer which has been exposed by peeling off part of saidrelease film along said slit is attached to the attachment site, theedge of said slit of the remaining release film can promptly protrudeoutward from between the attachment site and said adhesive layer, thewave pitch of said wave-shaped slit of said release film is 6 mm to 12.5mm, and the wave height of each said wave-shaped slit of said releasefilm is 4 mm to 8 mm.
 2. The patch according to claim 1, wherein twosaid wave-shaped slits are provided in said release film, and the twosaid slits are substantially parallel to each other.
 3. The patchaccording to claim 2, wherein the spacing between the two wave-shapedslits of said release film is 20 mm to 30 mm.
 4. The patch according toclaim 1, wherein the wave height of said wave-shaped slit of saidrelease film is 6 mm to 7 mm.
 5. The patch according to claim 1, whereinsaid patch has corners, said corners are rounded so as to have acurvature radius of at least 5 mm.
 6. The patch according to claim 1,wherein said adhesive layer is from 10 μm to 400 μm thick.
 7. The patchaccording to claim 1, wherein said support is from 0.01 to 5 mm thick.8. The patch according to claim 1, wherein the spacing between the twowave-shaped slits of said release film is 20 mm to 30 mm, the waveheight of said wave-shaped slit of said release film is 6 mm to 7 mm,said patch has corners, said corners are rounded so as to have acurvature radius of at least 5 mm, said adhesive layer is from 10 μm to400 μm thick, and said support is from 0.01 to 5 mm thick.